Virtual Advisors for Physical Activity Promotion in Aging Latino Communities BACKGROUND: Aging Latino adults suffer disproportionately from a number of chronic conditions (e.g., diabetes, obesity) improved by increased physical activities (PA) such as walking. Due to language, education, computer, and health literacy barriers, older Latino adults often cannot readily access typical health promotion programs offered in-person or online in U.S. communities. Lay health advisors (promoters in Spanish) offer a nationally recognized, culturally tailored and cost-efficient health behavior change model for Latino communities. However, as with all human delivered health programs, they impose constraints on participant schedules, and, even with careful intervention fidelity procedures in place, some variability in program delivery across advisors is inevitable. Computer-based culturally tailored physical activity advisor programs can potentially reduce human- to-human scheduling and fidelity constraints and extend program reach. In a recently completed 4- month experiment, a computer-based bilingual Virtual Advisor with touch-screen interactivity (no keyboard or mouse needed) was housed in a community center and programmed to tailor PA advice to the needs and preferences of low-income, aging Latino adults. The Virtual Advisor program successfully increased regular walking levels in participants compared to a health education control. OBJECTIVE: The primary study aim is to conduct a comparative effectiveness trial evaluating the 12- month impacts of the community-based Virtual Advisor PA program relative to a proven Lay Advisor program in a broader population of aging Latino adults. The secondary aim is to determine the comparative cost effectiveness of the Virtual vs. Lay Advisor programs. DESIGN: The 12-month randomized trial will enroll inactive Latino adults ages 55 years and older living near 16 neighborhood community centers (n=265/arm; 530 total). The primary outcome is minutes of walking per week, and additional outcomes of interest include BMI, sedentary behavior, functional performance, and health- related quality of life. Additional areas of investigation are to evaluate theoretically based and empirically supported moderators and mediators of intervention success and determine the potential generalizability of the interventions. IMPACT: The study seeks to demonstrate that a computer-based Virtual Advisor tailored to the needs of aging Latino adults can provide an effective and potentially cost-efficien alternative to Lay Advisors in community settings frequented by this population. The potential extended reach of such programs for use in a range of community settings (e.g., clinics, pharmacies, libraries) provides substantial promise for positively impacting the current health disparities gap.